NBC is making 4,500 hours of Olympics coverage available at NBCOlympics.com and the NBC Sports app, starting with preliminary soccer events on Wednesday, two days before Friday's formal start of the Olympics. The online coverage includes every single event live, as NBC continues a practice begun with the London Olympics in 2012 under new owner Comcast Corp.

For the first time, NBC is also offering some events in virtual reality through Samsung's Gear VR headset. NBC Olympics executive producer Jim Bell described the foray into virtual reality as experimental.

Much of this requires having a cable or satellite TV subscription, though as an alternative, you can sign up for Sony's PlayStation Vue service for $30 or $40 a month to get extensive access to NBC's app and website. Dish's Sling TV also offers some NBC channels online for $25 a month. In either case, you can cancel after the Olympics.

NBC is showing the Olympics on its over-the-air network and cable channels Bravo, CNBC, Golf Channel, MSNBC, NBC Sports Network and USA Network. It also has two temporarily channels devoted solely to soccer and basketball, plus one for events recorded in a higher-quality format known as 4K -- though you'll need a 4K TV for that. In Spanish, the Olympics are on Telemundo and NBC Universo. All told, there will be more than 2,000 hours of television coverage , with live streaming of all the permanent channels on NBC's app and website.

Here's how to watch the Olympics online, depending on the subscriptions you have:

OLD-SCHOOL OLYMPICSNetworks used to show the Olympics only on their over-the-air broadcast channels. But as the costs of Olympic rights rose, NBC started borrowing its cable channels to make more room for events it has already paid for.

NBC's over-the-air network remains the primary destination, though. That's where you'll find the most popular sports, including swimming, diving, track and field and gymnastics, along with the opening and closing ceremonies and the basketball finals. You can watch all 260-plus hours live for free if you have an antenna. You'll need a video recorder such as TiVo to record events for later. Some TiVo models give you online access to your recordings.

Beyond that, NBC's app and website offer highlights, interviews and features on athletes without needing a cable or satellite subscription. You'll also have full access to scores, schedules and guides to understanding obscure events. But for extensive video coverage, both live and on demand, you need to sign in with a cable or satellite TV account, beyond an initial grace period of 30 minutes, plus five minutes per day after that.

SLING TVThe $25-a-month Sling Blue package offers Bravo, USA and the NBC Sports Network on a variety of phones, tablets, personal computers and streaming TV devices. During the Olympics, Sling is adding MSNBC and CNBC for free. For $5 each, subscribers can get the Golf Channel and the Spanish-language NBC Universo.

The NBC broadcast network itself is part of the basic Sling Blue package, but is available only in the Chicago, Dallas-Fort Worth, Hartford, Conn., Los Angeles, Miami, New York, Philadelphia, San Diego and Washington markets. The Spanish-language Telemundo network isn't available anywhere, nor are the temporary soccer, basketball or 4K channels.

The catch is you must watch everything in real time. Sling isn't offering any on-demand video coverage, nor will Sling's password give you access to extensive video on NBC's app or website or VR through Gear VR.

PLAYSTATION VUEVue acts more like a cable service by giving you sign-in privileges for video and VR. But there's no cable to install -- or disconnect after the Olympics. In fact, both Sling TV and PlayStation Vue offer free weeklong trials, so you can game the system by staggering the trials during the two-week Olympics. (You didn't hear it from us!)

Vue offers most NBC cable channels, including the temporary soccer and basketball channels, as part of its basic plan. It costs $30 or $40 a month, depending on the market. NBC and Telemundo stations are offered in more than a dozen markets each. You can get Golf Channel and NBC Universo for an additional $5 each.

The catch is you need a PlayStation, Amazon Fire TV or Roku device to sign up, after which you can watch on iPhones, iPads and other devices, too. Vue offers an online DVR with unlimited storage, but recordings expire after 28 days. There may be restrictions on viewing recordings or real-time channels from outside your home -- though NBC's app is available for that.

TRADITIONAL SUBSCRIBERSMany cable and satellite providers will add a 4K channel for the Olympics to show selected events, typically with a one-day delay. For VR, viewers will have to get NBC's app through the Oculus store on Gear VR and sign in with their cable or satellite account. Again, these will be offered with a one-day delay. NBC isn't directly involved with either the 4K or VR production, but will rely on international feeds provided by the International Olympic Committee's Olympic Broadcasting Services.

"The Olympics serve as a great ground to test new things, try new technologies, new cameras, new traffic systems and you're going to see that with 4K and VR," Bell said.

Most of the online video will come from OBS as well. So while NBC's announcers cover an event live on television, with an online simulcast, NBC's website and app will usually carry the international feed. That makes the digital destinations a good way for immigrants to follow athletes from their home countries. On TV, expect most of the focus to be on Americans and top contenders.